Those Bloody Promises
by herwhiteknight
Summary: Set after the season finale and after Cosima confesses to Sarah that she is sick. Snapshots of Cosima and Sarah's relationship after the finale, with my own little twist at the end.


A/N: The parts where I'm talking about the cure... just keep in mind that I have absolutely no idea what I'm talking about so just... let it go, okay? (starts humming Elsa's song) Uhm yeah, I just wrote whatever felt right so yep. That's about that.

* * *

Sarah was standing at the window of Felix's apartment, her gaze roaming sightlessly over the city landscape. The city was burning. Or, at least, it looked that way to Sarah, what with the way that the rays of the sunset hit the bricks and refracted on the glass of grimy windows. She had been through too much to see the beauty in much of anything anymore, finding it easier to imagine destruction instead.

"Sarah, are you alright?" Cosima called from behind her, causing her to barely turn. Only when a slight cough sounded from behind her did Sarah allow herself to pull her blank stare away from the cityscape. "You've been standing there awhile."

Sarah allowed herself a small shrug, a simple, one-shouldered thing that seemed to convey her apathy. "I can't focus on anything, Cos," she admitted, her gaze tracing up from the floor to meet Cosima's eyes. "It's been ten months and we still don't have anything to go on."

Cosima just looked at Sarah for a moment before opening her arms to the other woman and pulling her into an embrace. This kind of comfort had become natural to the two of them, developed over months of despair and hopelessness. It was the only thing that kept either of them sane.

"Kira didn't give up on you while you were gone for just as long, Sarah," Cosima assured softly, her gentle voice sounding just beside her ear. Sarah sank into the comfort, pressing her cheek against Cosima's rough dreads, breathing in the familiarity of it. Whatever else happened, she had this at least. "We'll find her," Cosima repeated, pulling her closer with a hand on the back of her head while the bloody orange rays of the sunset fell around them.

* * *

"No Sarah, you don't get it! I'm getting worse and nothing that Delphine and I are doing is working!" Cosima strode about the apartment, empty once again of Felix's presence. After Delphine and Cosima discovered the patent, she had no choice but to remain holed up with him, after much grumbling. "I'm... going to die," she said, stopping suddenly as the realization hit her like an iron fist.

"Don't say that," Sarah stopped in the act of making coffee to look sharply over at Cosima. "You two brainiacs will figure something out," she said with a small grin.

"Sarah, we've tried everything!" Cosima replied, her voice frustrated and small and scared all at once. "That's it, we've exhausted everything, every hypothesis and theory... nothing! We can't think of anything else to try."

"You'll find something," Sarah told her firmly, as she stepped towards her sister. The sight of the smallest tear clinging to the edge of her lashes had her quickly wrapping her arms around the other woman, tightening her hold until she felt Cosima relax into the only thing that kept them sane.

"You can't be so sure," she said, her voice muffled by Sarah's shoulder, where she was resting her forehead. "You don't know anything about science or biology or anything so-"

"Oi," Sarah exclaimed softly, tugging on a couple of Cosima's dreads, forcing her to look up into Sarah's eyes, albeit with a disgruntled expression as she moved one of her arms so that she could reach around herself to swat Sarah's hand away. "You told me that we'd find Kira, yeah?"

Cosima breathed in slowly, searching her memory for the conversation that they had had, that one day four months ago where Sarah's listlessness had caused her to almost give up all hope of finding her daughter. "I did tell you that," she said slowly, watching Sarah carefully, her eyes flicking back and forth between Sarah's.

"And we found her, yeah?" she said, smiling encouragingly, sliding her arms away from her slim frame and linking their fingers together instead. Cosima just nodded back, hope creeping into her expression at Sarah's words. "Because you helped me get back on my feet, Cos. Now I'm here to do the same. Don't give up, yeah?"

"Thank you Sarah," Cosima nodded, feeling resolve anchor at the base of her spine as she stood taller.

"Here for you Cos," she replied, a confident smirk quirking one side of her mouth upwards. "Now call Delphine, alright? I think you've got some research to do?"

* * *

She had been up late, comforting a sick Kira when her clone phone rang at two in the morning. The number showed up as Cosima. The fact that she was calling now, in the middle of the night, had Sarah slightly worried. They had experienced several weeks of relative peace with nothing to worry about, what with Kira safely under Sarah's wing and a cure found for Cosima's sickness.

She slid out of bed carefully as not to wake her pale little girl and grabbed her phone as she slipped outside, leaving the door open a crack so she could still see Kira in her bed while she talked. "Cosima, hello?" she answered in a hushed tone.

But it wasn't Cosima who answered her greeting. A low, French accent answered instead, the speaker clearly panicked. "Sarah, I didn't know who else to call. It.. Cosima, she..."

"Wha... whoa, slow down," Sarah spoke into the phone, snapped out of her groggy haze by the urgency that was obvious in Delphine's tone. "What's going on Delphine?"

"The apartment. Felix's. You.. you must come right away, d'accord? Maintenant!" she commanded, nerves driving her words up an octave.

Panic flooded through Sarah's veins at that moment as well. Whatever had the Frenchie worried was bound to be trouble. "I'm coming right away," she answered then disconnected the call as she pushed into her foster mother's room.

"S?" she called quietly, padding over to her sleeping form, the image appearing grey in the half-light of the night.

Mrs. S jerked awake quickly, her hand flying over to the edge of the bed where Sarah could just barely make out the butt end of her shotgun. When she realized it was just Sarah, she relaxed and sat up slowly. "What is it love?" she asked, reaching out and taking Sarah's hand. "Is something wrong?"

"It's Cosima," she said before elaborating as much as she could, "Something's... well, I don't know what's wrong. But Delphine called and said that I had to go over to Felix's apartment right away. Watch Kira, alright? Tell her that I'll be right back. And that's a promise."

The first thing Sarah noticed when she arrived at the flat was Cosima's face. Her eyes didn't even glance up from her screen and she didn't even bother returning Sarah's greeting as per usual. "What's wrong with you Cos?" she asked nervously, "What's the matter?" When Cosima didn't reply, Sarah looked to Delphine, but the French woman just shrugged as she worried at her bottom lip before answering.

"She wont even tell me what's wrong," she said, putting a hand on her hip as her other hand gestured nervously, "She was staring one moment at her computer and the next she just... went blank and told me to call you."

"Cos," Sarah said, crossing over to the couch so she could sit down beside her. She put an arm around her shoulders and pulled her into her side before continuing, "We're safe now, yeah? Kira's been found, you've been cured and we're alright. I promise."

"Yeah, I've been cured," she muttered, staring at her screen still. Sarah glanced at the screen, but saw nothing unusual about the numbers that blinked up from it.

"What's that supposed to mean? Of course you've been cured Cos, you and Delphine found the cure a few weeks ago!"

Cosima pointed to a highlighted string of numbers, leaning out of Sarah's hold for a moment before falling back against her, "That's you, Sarah."

"Alright...," she said slowly, looking at the short string of characters that Cosima had noted as her tag number.

"And that," Cosima said, slipping into a listless tone as she carried on, highlighting another section of seemingly random numbers, "Is the disease."

"The... no, Cos, that's...," Sarah looked over at Cosima, her lips pulled into a tight frown. "That can't be right!"

"It is," Cosima replied heavily, clicking elsewhere on the screen so that the numbers were lost amongst all the others, "You have it too."

* * *

"Cosima, I don't understand," Sarah snapped a few days later as she paced around in Felix's flat. Mrs. S had taken Kira out for the day, giving Sarah the space that she and Cosima needed to figure everything out. "Why can't you just use whatever worked on you for me?! Why haven't you cured me yet, Cos!"

"Sarah, calm down," Cosima said, putting up a hand, her fingers trembling in midair, "I can't... it's not... something's wrong with it!"

"It?" Sarah practically yelled, "What, it? Cosima, please, quit messing around and fix me! Why has it been taking so bloody long?!"

"I... Sarah, I can't! I had to create the cure from scratch for god's sake! It was tailor made, alright, it had to be! And... and the disease... it seems to be affecting you differently than me!"

"We're bloody identical, how in god's name is that even possible?!" Sarah growled, turning to Cosima who sat on the couch, her laptop open in front of her, but her eyes were trained on Sarah as she paced around the room like a caged lion.

"The DNA sequence," Cosima said slowly, the gears turning in her head, "The bar code I told you about. That has to be it," she snapped her fingers and highlighted the sequence in Sarah's DNA that tagged her as Sarah and not as Cosima or Alison. "It's their way of controlling the clones, it has to be."

"I don't care what it is!" Sarah yelled at her, hands balled up into fists, "Stop trying to hypothesize everything and just get to work, yeah?!"

"It's not that easy, Sarah!" Cosima snapped back, exasperated, "It took Delphine and I weeks creating the cure that was compatible with _my _bar code! It'll take me just as long to restring the cure to have it coded to something that will work with your bar code!"

"Weeks?" Sarah asked, "Weeks?! Cosima, we don't bloody have that kind of time!"

"Now, we don't know how much time we have, exactly-" she began, trying to pacify the other woman, but Sarah cut her off.

"Don't do this to me, Cos," Sarah snarled, but there was a plea underneath the anger, "Don't let me die. I can't leave Kira motherless. Not again..."

"Sarah I...," she began, but found herself at a loss. She shook her head and took a breath, "I need to get to work."

* * *

"Sarah, I'm.. so sorry," Cosima said softly six days later, sinking down onto the edge of the bed where Sarah was lying prone.

She coughed weakly as she reached out for Cosima's hand. "You didn't find anything then," she said quietly. It wasn't a question. As smart as Cosima was, the disease had inexplicably deteriorated Sarah's system much more quickly than it had deteriorated Cosima's. The other woman just shook her head, her face falling. "I'm going to die." It also wasn't a question.

"Sarah, I-" Cosima began, squeezing her hand gently for a moment before Sarah stood suddenly, pulling her hand from Cosima's grasp. "Where are you going?" she asked, watching in concern and fear as Sarah stumbled away from her.

"I need to see Kira," she insisted even as she had to catch herself against the back of the couch as she stumbled towards the door. "I need to see...," she panted as she pushed herself back up to a standing position.

"Sarah... Sarah stop!" Cosima told her sharply, reaching out and grasping her forearm, putting her other arm around her shoulders to steady her. "You can't expect to just go walking around like that, you haven't moved from that bed since I started reworking the cure!"

"Get off me!" Sarah growled, uncaring of the blood that coated the back of her throat that told her that Cosima was right. "I have to see my daughter."

"Will you just-" Cosima began and would have thrown her hands up in the air in exasperation had she not been keeping a firm grip on Sarah's frame that was shaking from exhaustion.

"Leave me the bloody hell alone Cos!" Sarah exclaimed, belligerently shrugging out of Cosima's steady hold. She managed one wobbly step before her arms instinctively reeled backwards to latch onto Cosima's shoulder.

"I'll go," Cosima said softly after a moment.

"You what?"

"I know how much she means to you," Cosima explained, "But Sarah, I also know how weak you are. I've been there, right, not that long ago actually. You can't go. But I can go for you."

"But... if something happens while you're out.. to me, I mean," Sarah mumbled quietly, looking over her shoulder at Cosima who was steadying her once again.

"That's not going to happen," Cosima told her firmly, pulling slowly at her shoulder until Sarah managed to twist around, allowing Cosima to pull the frail woman into her arms. Her heart sped up in panic as she felt Sarah's body against her own, how she could almost count Sarah's ribs by the feel of their ridges alone. "I'll go to your foster mother's house, get Kira-"

"And S. Her too," Sarah sighed from within Cosima's hold.

"And Mrs. S," Cosima nodded as she continued, "Then the three of us will come right back here and you can... um, say your.. your goodbyes."

"Alright Cos," Sarah nodded, the movement so faint that Cosima barely registered it. "You should go then."

"Sure," Cosima nodded a couple of times, to bolster her confidence maybe, before guiding Sarah back to the bed. Once she was sure that Sarah was comfortable, she turned to get her coat, pocketing the address that Sarah had penned out in wobbly script.

Before she could even head out the door, Sarah called out again, "Cos?"

"Yeah Sarah?" she replied, trying to hide the tremor in her own voice. _She'll be okay. She has to be._

"I... I love you Cos. You've always been... well," Sarah swallowed, the sharp tang of blood against her tongue hardly registering, "You're.. family to me."

Cosima's heart swelled with an overwhelming mix of grief and love as she rushed back over to the punk woman and smiled sadly at her. "I love you too," she murmured, reaching out and brushing stray strands away from Sarah's face before leaning down and kissing her forehead. It was something that Cosima wasn't used to, but Sarah had always done in times past when Cosima needed comfort, so she thought she'd give it a try. As she stepped back and noted Sarah's content expression, the most peaceful she had seen it since Cosima had told her about the disease, she knew it was the right thing to do. "Just rest for now. I'll be back before you know it."

Sarah hummed behind her, the sound echoing horribly in her chest cavity as Cosima pulled the loft door shut behind her, locking it and pocketing her key. And as Cosima pattered down the stairs to the outside, her mind kept whirling through all the different strings of code that she hadn't tried and whether this might work if she just replaced those two letters for that one. It hadn't sunk in yet that, at any moment, Sarah could be breathing her last.

* * *

She had stood for something. To.. do something. What... what was she standing for? She had gotten out of bed. Why? _If Cosima were here, she would kill me, _Sarah thought in one moment of clarity. She heard Cosima's voice telling her to lay back down, that she would be back. She would, she promised. _But she didn't, did she? _Didn't matter. She should still get back into bed before she really hurt herself. But she _had _gotten out of bed for something, she had. What was it?

Weakness wracked her body then, turning her legs into jello. Red jello. Something struck her mind just then. Red jello. It was significant, important somehow. It held meaning to her beyond this moment. A silver spoon stuck out of it and sugar. There was sugar involved somehow. Then it was blonde. The jello was blonde. But she had gotten out of bed for something. _What did I get out of bed for?_

Sarah's mind was a mess, that much she could distantly observe. But her body... she felt great. Better than she had in a long time. She was warm and light, like she could do anything. And she wanted to. She hadn't done anything in awhile, had she? So she would. She would do something. Anything. Because she felt so... free. Like she could go anywhere. The stars were waiting for her. They were right in front of her eyes, like they were surrounding her, swarming in her brain. She wanted to touch them. So she reached... and reached into blackness as she heard a faint thump of something _heavy _hitting the floor.

And the blackness was still surrounding her. And from that blackness came stars.

* * *

"But this is Uncle Felix's place," Kira said as Cosima pulled up haphazardly in front of the gratified garage door. "Is mummy here, with Uncle Felix? And why couldn't she come back home instead? Why did you come pick me up?"

"Hush love," Mrs. S said from the passenger seat as she reached back to undo Kira's seat belt to find that the little girl had already unbuckled herself and was climbing out of the car. "Just wait for us monkey," Mrs. S called as she looped around the front of the car, meeting Cosima by the driver's side as she locked it. "How is she?" she asked in an undertone, the lines on her face betraying her worry.

"As well as can be expected," Cosima answered, her lips forming a thin line.

"Which, I gather, isn't very well at all," Mrs. S said, before sighing softly. "Why is it, Cosima, that you have been unable to cure my daughter like you have cured yourself?"

Cosima flinched at the harshness in Mrs. S's tone, but knew that she couldn't blame the woman. "It's got something to do with.. well I.. don't know actually," Cosima began confidently, but trailed off near the end, her voice swamped with hesitation and fear. It was truly the first time that her science had failed her. "It might be because she's fertile but... I don't know what else it could be."

"Mummy!" Kira suddenly yelled from the base of the concrete steps where she previously had been bouncing in excitement. Her fingers were curled around the wire mesh, yanking on it as she tried to pull it open.

"What is it love?" Mrs. S hurried over and gently pulled her fingers away from the metal so that she wouldn't cut herself.

"Something's happened to mummy!" she cried, tear tracks already trailing down her cheeks.

"Sarah...," Cosima muttered, already slipping through the door and heading up the stairs. "Keep Kira back until I figure out what's going on!"

She raced up the steps, anxiety driving her heart up into her throat as she skidded around the corner and fumbled with the keys. "Sarah?!" Cosima yelled, pounding on the door for a moment before shakily inserting the key into the padlock on her second try, clicking it open. She knocked the whole system to the ground before pushing back the heavy metal of the door, cutting her palms in the process. "Sarah!" she yelled again as she stepped into the open space of the apartment, trying to take every detail in at once.

It wasn't until her third hasty sweep of the room that she saw it. Saw Sarah. Flat out on the floor, a small bloodstain by her nose and mouth. A noise behind her on the stairs. Mrs. S and Kira. "Keep her back!" Cosima exclaimed, her voice strangled as she rushed forward and grabbed Sarah's shoulders, pushing her onto her back. "Sarah?!" she shouted again, dimly aware that if Sarah were conscious, then she was shouting in her face. _If _she were conscious. _But no. She had to be... she couldn't be.. she didn't just-_ "Sarah wake up!" Cosima found herself screaming again, tears streaming down her face as she pounded at Sarah's chest, her high school first aid course forgotten in her panic. "Wake up you asshole!"

"Let me go! I need to see mommy! Mommy! Let me see her, I need to see my mommy!" Kira's raw and panicked voice shot in from the hall outside, followed by Mrs. S's low voice in attempt to calm her down, to keep her away from the sight of her mother limp in Cosima's lap, her lower face crusted with droplets of dried blood, a sharp contrast to the paleness of the rest of her skin.

Sarah's eyes snapped open then, at the sound of her daughter's cries. "Kira?" she mouthed, no sound coming out at first as she tried to fill her lungs with air.

"Oh my god, Sarah, christ," Cosima swore, her poised fist dropping in midair as she helped Sarah up into a sitting position, "Oh my god, you're alright, I thought..." Cosima just looked at her as Sarah got control of her body again, supporting herself as she sat.

"Still here," Sarah smiled weakly, looking down at herself then back up at Cosima who suddenly lunged forward and pulled Sarah into a sloppy hug that was all awkwardly angled arms and tear stains. "But not for long if you squeeze the air right out of me Cos," she laughed and Cosima laughed as she eased out of the embrace, opting for an arm around her shoulder as they sat on the floor, her other free hand pulling across her damp cheeks.

"Mommy!" a little girl's voice shouted and Cosima watched as Sarah's face lit up, turning her face towards the source of the sound as if she couldn't believe it.

"Kira!" she exclaimed as loudly as her abused throat would allow, catching her little girl in her arms.

"Careful Kira, now, love," Mrs. S said gently as she followed behind her into the room, "Mummy's still weak."

"I'm strong enough for this," she assured gently as her little girl settled into her lap, arms around her middle, head pressed flat against her mother's chest, listening to the slow beating of her heart, the rattle in her chest.

"Mum," the little girl said as she pulled her cheek from Sarah's chest, "Your insides sound all funny."

Sarah shot a look over at Cosima, worry crossing her face which was concealed as Kira looked back up at her, her small expression blinking with curiosity. "Come here for a moment, love," Mrs. S said softly when she caught the look between the two women.

"Go on," Sarah encouraged, kissing her on her head before nudging her off of her lap. Mrs. S took her over to the kitchen area to fix her a sandwich while the other two women talked.

"Cos... am I... safe?" Sarah asked worriedly, feeling every breath rattle horribly in her chest.

"I'm still no closer to finding a cure," Cosima replied, studying the way that Sarah's chest rose and fell in a surprisingly regular manner despite the wheezing sound that escaped from her partially parted lips. "But the fact that you didn't die when I first found you lying on the ground is..."

"A miracle, yeah," Sarah nodded, watching Mrs. S and Kira talk softly in the kitchen, the older woman shooting glances over Kira's head every so often, her eyes flashing in concern.

Sarah felt Cosima's hand at her waist, tugging at the hem of her shirt. "May I?" she asked, her fingertips brushing against her back.

"Yeah, sure," Sarah shrugged and Cosima lifted the back of Sarah's shirt and pressed her ear to her back, just below her left shoulder blade. She heard the rhythmic thud of her heart and the rattle of her breath; the things that Kira had proclaimed to sound 'all funny'. She pulled back with a sigh and let her shirt fall back into place. "Well?" Sarah asked, obviously trying to mask her concern, her fear.

"I'm not a doctor Sarah," Cosima answered quietly, "But... your breathing. It's getting worse, isn't it?"

Sarah just nodded silently before leaning in close. "Just.. promise me one thing, Cosima, yeah?"

"Anything, yes," Cosima nodded emphatically just like she had the first time they met in that bar. Sarah shot a glance past Cosima's shoulder where Mrs. S and Kira were talking softly before taking in a small breath and murmuring her wishes softly into Cosima's ear.

"No arguments Cos," Sarah said gently, taking the other woman's hand in hers. "Just do this last thing for me, yeah?"

"I...," Cosima began, her voice catching, well aware of what Sarah's request meant. She knew she was going to die and she knew that Cosima would not be able to cure her in time. She swallowed hard before nodding once gravely. "I promise."

* * *

_I can't focus on anything, Cos._

"I know the feeling Sarah," Cosima muttered as the bloody rays of the sunset hallowed around the stone slab before her, making it hard to read the words chiseled there. As if she could focus on them anyways without her vision blurring from another bout of tears. Besides... she already knew what they said anyway, had memorized them long ago.

_In Loving Memory_

_Sarah Manning_

_March 15, 1984 – February 24, 2014_

_She was only One._

"What are you thinking about, cherie?" a soft voice asked from behind her.

Cosima didn't even turn as Delphine's footsteps drew closer, nor did she react when she felt her hand touch her face gently. She closed her eyes and tried to take comfort in the way that Delphine softly stroked her cheek, but found it to be almost impossible. "I want to know why I'm still here and Sarah isn't," she said after drawing in a shaky breath. A breath that no longer filled her lungs with blood. She would never take breathing for granted ever again. Not when Sarah was lying just below their feet, her lungs filled not with air, but with blood and dirt. "It isn't fair Delphine!" she yelled suddenly, kicked at the grass at the base of Sarah's tombstone. "I was supposed to protect her, to keep her safe! That's what we were to each other, what we promised each other we'd do! She kept me safe but I couldn't keep her safe and..."

"Cherie..," Delphine murmured, drawing the other woman close with an arm around her waist, "It is not your fault, you cannot-"

"It is my fault and I can blame myself!" she snapped back, stepping abruptly out of Delphine's embrace, hugging her arms around herself as she sniffed back tears, "I managed to cure _myself _just fine! What was so different about Sarah that I couldn't... that I didn't..."

"You did your best, Cosima," Delphine replied but Cosima just shook her head and glared at the space just above the gravestone, arms still folded in on herself.

After a couple of quiet moments, Cosima softened and allowed herself to shuffle back into Delphine's arms, words slipping out from her lips as she pressed her back into Delphine's chest. "She once told me not to leave Kira motherless you know." Delphine stayed quiet and by her silence Cosima could tell that she was waiting for further explanation, "And... and two days before she...," Cosima swallowed hard and continued on, "She asked me.. made me promise to be a mother to her little girl."

"Oh, Cosima...," Delphine murmured, pressing a kiss to her temple as the other woman inhaled sharply and fought another round of tears.

"I don't know how to be a mother, Delphine," Cosima exclaimed, her words dissolving into sobs, "I don't know how to love like that! I heard Sarah talk about Kira and I knew just from the way she talked that she loved that little girl with everything and now... now you've made me promise to.. to.. be a mother and Sarah I just.. I don't know how! How can you make me promise that?! How could you leave me with that?!"

Delphine kissed her temple again and squeezed her around her waist before pulling her around so that her back was to the grave, her watery eyes gazing up into Delphine's glassy ones. "How could she leave me...," Cosima sobbed brokenly, throwing herself into Delphine's arms and breaking down on her shoulder. It wasn't the same, that hug. The height was wrong and the arms were missing the strange sense of power and strength that Sarah possessed, but it was all she had left.

"You do not have to do it alone, cherie," Delphine whispered into her ear while Cosima clung with weak fists to the fabric of her sweater. "I will be with you in every step, Cosima, I promise."

And standing in front of Sarah's grave, wrapped in Delphine's false grip, Cosima cried even harder. Because if there was one thing she had come to learn about promises it was that they were easily broken.


End file.
